I don't think that answering quickly is necessarily the best
I don't think that a quick solution is necessarily the best solution
早く解決しようと焦って出した答えが、よくないこともあります。を伝えるため、下記のパターンが適切だと思います。
I don't think that 〜 is necessarily 〇〇は
〇〇は〜とは限らないと思います。
〇〇=早く答えを出す
〜=最善
I don't think that answering quickly is necessarily the best
〇〇=早い解決
〜=最善な解決
I don't think that a quick solution is necessarily the best solution
ご参考になれば幸いです!